The present invention relates to high performance electric power cables and connectors and, in particular, to an improved cable and connector system that can endure rigorous tension and compression forces and which is easily and safely transportable.
The military, as well as commercial industries such as the mining industry, have a need for reliable, portable cable and connector systems for carrying electric power to remote locations. It is necessary that these cable systems be easily manipulable and safely transportable. Accordingly, the cables used in such systems should be relatively flexible and be capable of withstanding the harsh environmental conditions and severe abusive treatment which is characteristic of operations in mining or in the military.
For instance, power cables in the field may be exposed to extreme crushing and torsional loads created by heavy vehicles traveling across the cables. The cables may also be exposed to other compressive forces such as those created upon impact by sharp objects propelled at high velocities. In addition to these compressive forces, the cables must also be capable of sustaining high tensile forces that are typically created when the cables are deployed for use. Sometimes it is necessary to suspend a cable across a long span, for example, across a ravine or river, in order to provide power for use on the opposite side. Typically, even the weight of the cable alone may be sufficient to produce tensile loads which are beyond the tensile limit of the cable. Therefore, it is often necessary to provide support for the cable for even a short span.
Conventional portable power cable systems often fail under the harsh conditions described above. Typically, the cable systems use twisted strands of copper wire for both conducting electricity and for carrying tensile loads that are applied to the cable. While copper can be a good conductor of electricity, it is not a relatively strong structural material and is thus unable to withstand significant tensile loads. Accordingly, the copper wires of conventional cables tend to break under severe compression and tension forces, thereby rendering the cables unfit for transmitting electricity.
The normal cable system includes connectors for interfacing the cables with either a power supply, a device to be powered or another cable. The type of connector used with the cable can have a substantial effect on the survivability and effectiveness of the cable. A common failure with conventional cable systems is the separation of the connector from the cable in the presence of large tensile loads. Typically, the conventional cables are designed such that the internal conductors support the principal tensile loads. The conductors continue to support a substantial portion of the tensile loads even when the cable is attached to the connector. There is no effective transmission of tensile loads to and from the conductors and the connector. As a result, the conductors often eventually fail under the tensile loads, thereby causing the entire cable to separate from the connector.